Selenite
Selenite is one of the three forms of pure natural crystalline gypsum, with one other, satin spar having a very similar features, the other natural form is gypsum rock which is commonly crushed and used in the manufacture of plaster products.
In old English gypsum was referred to as spear stone (spærstn) because of its crystal spear-like projections, of which selenite and satin spar have the most notable. Selenite crystals are much rarer than satin spar crystals, whilst gypsum rock is relatively common. Other forms of crystalline gypsum are known as tabular gypsum, which is normally shorter blocks of satin spar, whilst desert roses, form with grains of sand and gypsum flower which are referred to as crystal habits.
Selenite crystals form in large flat, transparent crystals, often called plates or windows, whilst Satin Spar crystals are fibrous and white, often appear as raw rulers or wands which can be polished into palmstones or spheres. The naturally large flat transparent form of selenite crystals, might also be called Lapis Specularis a form of selenite that was put to good use by the Romans in the construction of specularia (sometimes referred to as specularium), which included the first types of windows before the development of glass for use in glazing, it was used to construct Roman winter gardens for horticulture.
[edit] Related articles on Designing Buildings
- Botanical gardens
- Construction materials.
- Conservatory.
- Drywall construction.
- Garden greenhouse.
- Gypsum.
- Hydroponics and buildings.
- Lime plaster.
- Minerals of local and national importance.
- Mortar.
- Permission for mining or working of minerals.
- Plaster.
- Specularium.
- The secret life of the Georgian garden.
- Types of glass.
- Winter gardens.
Featured articles and news
What it is and how to use it.
Investors in People: CIOB achieves gold
Reflecting a commitment to employees and members.
Scratching beneath the surface; a guide to selection.
ECA 2024 Apprentice of the Year Award
Entries open for submission until May 31.
UK gov apprenticeship funding from April 2024
Brief summary the policy paper updated in March.
For the World Autism Awareness Month of April.
70+ experts appointed to public sector fire safety framework
The Fire Safety (FS2) Framework from LHC Procurement.
Project and programme management codes of practice
CIOB publications for built environment professionals.
The ECA Industry Awards 2024 now open !
Recognising the best in the electrotechnical industry.
Sustainable development concepts decade by decade.
The regenerative structural engineer
A call for design that will repair the natural world.
Buildings that mimic the restorative aspects found in nature.
CIAT publishes Principal Designer Competency Framework
For those considering applying for registration as a PD.
BSRIA Building Reg's guidance: The second staircase
An overview focusing on aspects which most affect the building services industry.
Design codes and pattern books
Harmonious proportions and golden sections.
Introducing or next Guest Editor Arun Baybars
Practising architect and design panel review member.